Change-speed gear, especially for motor vehicles



July Z, 1940- T. KUMMlcH 2,206,409

CHANGE-SPEEDGEAR, ESPECIALLY FOR MOTOR VEHICLES med ual-ch 1a, 193s yPatented July 2, 1940 oFrlcE CHANGE-SPEED GEAR, ESPECIALLY Fon Moron VEHICLES Theodor Kmmich, Stuttgart, Germany, assignor to Daimler-Benz Aktiengesellschaft, Stuttgart- Unterturkheim, Germany Application March 1s, 193s, serial No. 196,665 In Germany March 18, 1937 s claims. (ci. u sss) e This invention relates to a change-speed gear especially for motor vehicles, with a change clutch shiftable in both directions out of its neutral I position for alternately changing two speeds, andv I it consists substantially in that-the change clutch is constructed at the same time as a gear wheel with which, when the change clutch is in its neutral position another gear wheel can be brought into mesh especially for Vobtaining a reverse speed.

The invention also relates to a change-speed gear, especially Vfor motor vehicles, with an outer clutch member shiftable for changing one or two speeds, slidably mounted. on an inner clutch member constructed for example as a synchrou nizing device and connected with the outer clutch member for example by an arrangement, automatically disengageable under increased changing pressure, the invention being characterized .substantially in thatvfthe outer clutch member shiftably mounted on the innerclutch member is constructed at the same time as a gear wheel for obtaining another speed, especially a reverse speed. y v

As compared with the known gears the gear according to the invention is much'shorter and simpler, as by constructing the clutch member as a gear wheel, an additional space for this wheel is saved. At the same time the gear is more silent owing to the shortening of its shafts and distances between bearings. Moreover, the

invention enables an additional speed to be incorporated in the gear without adding to the length.

The clutch memberprovided with the toothed s rim preferably serves as gear wheelv for the reverse speed, as the toothed portion can, in this case, be provided with straight teeth without any disadvantages resulting therefrom, whereas the gear wheels for the forward speeds are preferably formed by pairs of biased permanently meshing gear wheels and cooperating lfor example with 'synchronizing devices. Furthermorev the arrangement in combination with the reverse speed is particularly advantageous as far as a slide wheel is not necessary either on the main shaft or on the countershaft for the engagement of the reverse speed which can be effected by shifting the usual third wheel.

5o An embodiment of the invention is illustrated by way of example in the accompanying drawing, in which:

Fig. 1 shows the gear in longitudinal section. Fig. 2 shows a detail of Fig. 1 on an enlarged n scale.

Fig. 3 shows-a schematic diagram of the path followed by the control lever.

Fig. 4 shows the locking device for the change rods.

The driving shaft b is journalled ina case a 5 which accommodates. the countershaft c and the driven main shaft d. The two first mentioned i shafts are permanently connected by the two gear wheels ei, e'z with biased teeth, whereas three pairs of permanently meshing biased 10 toothed gear wheels fi, f2, g1, y2 and h1, h2 are provided between the driven main shaft d and I the counter-shaft c, the gear wheel f1 being loosely rotatable on the main shaft and the gear wheels y2 and h2 loosely rotatable on the counter'- 15 shaft, Whereas the other gear wheels are keyed on their shafts.

A rim of claws i and a cone lc are rigidly connected with the shaft b and the gear Wheel'ei. and a rim of teeth Z and a cone m with the gear 20 wheel f1. Between the two gear wheels an inner change clutch member o is splined on the main vshaft d and provided with conical faces p and q and equipped with outwardly directed keys 1'. On these keys a second outer change clutch member 25 s. with inwardly directed keys r1 is mounted and coupled with the inner change clutch member o by a ball t engaging under spring pressure in a recess in the clutch member s.

'I'he outer clutch member also has a toothed 30 rim u with straight teeth. Opposite this rim a gear wheel vis keyed on the counter-shaft, and

, adapted tobe brought `into indirect engagement with the rim u or with the change clutch mem- -ber s constructed as gear wheel by a slidable gear $5 wheel w which is mounted in the usual manner onanother shaft, not shown in the drawing.

As shown inFig. 1, a change clutch comprising the two separate clutch members :c and y is arranged ina suitable manner between the gear 40 wheels gz and h2. However, in this instance the outer change clutch member y is provided with a groove z for a control fark instead of with a toothed rim.

For changing the gear, the lever I Il shifts a selector plate II provided with balls I2 and stops I3, and this plate shifts the three control rods I4, I5 and I6 in some manner rnother which isA not of particular interest here. A fork I 1 is connected with the control rod I4, straddles the change clutchmember s and servesI for shifting this member in a manner which will be hereinafter described in detail.v A fork I8`is connected with the rod I5 and engages in the groove z of the change clutch member y. Finally a lever into simultaneous engagement with the gearv wheels u and v.

For locking the change rods so that only one lcan be shifted out of its neutral intermediate position, two balls 2| and" 22 are provided in known manner, these Aballs engaging in corresponding recesses in the neighbouring rods, and they are held at a predetermined distance apart by a pin 23 fixed in the middle rod. The balls ilv engaging in the recesses in the change rods under spring action serve in known manner for determining the individual change positions.

The gear operates in the following manner: The positions of the lever I0 for engaging the diiferentspeeds are illustrated diagrammatically in Fig. 3. For engaging the ilrst speed the lever III, and through the intermediary of the right abutment I3 the control rod Il, are shifted towards the right. The fork I1 shifts also towards the right the outer clutch member s constructed as gear wheel u and, through the intermediary of the balls t, likewise the inner ch'ange clutch member o. Thus the conical friction surface q is first pressed against the corresponding friction surface m of the gear wheel fr so that this'gear wheel connected with the shaft b through the 80 intermediary of the gear wheels er. en. 'fr rotates in the same direction as the shaft d. Under a slightly increased-changing pressure the ball t .is pressed aside, so that the outer clutch member s is uncoupled from the inner clutch member o and its inner grooves r1 can be brought into engagement with the claws I. The first speed is' then produced by the gear elements b-eiez-e-fnl-fi--s-o-d.

. In a similar manner the second gear is engaged by. shifting towards the left thecontrol rod II and consequently the change clutch z, u,

so that the pair of gear wheels gz, ai 'become operative. The third speed is obtained by shifting towards the right the control rod II with the result that the pair of gear wheels ha, h1'

are engaged in'a corresponding manner. In the fourth, direct gear' the shafts b and d are coupled by means 'oi'. the claw members i, n after previous synchronization by the conical surfaces p, k; in .thatl the lever Jl, through the intermediary of the'stop I3 arranged onthe selector plate II, shiftstowards the left the control rod I4 with the fork I1 and consequently the clutch member I1.

Thestops Il are arranged in such a manner that they move the'control rod I l-in the ilrst and fourth speeds. 'and the control rod Il in the second and third speeds. The balls I2. serve foi;y ,allowing the control rods to be shifted out of their medium position by the corresponding stops only during the chemins stroke for one speed. It is possible, by thisknown change-speed method, to arrange inwards the gear wheels fr, fz for -the first speed, and the gear wheels In, hz for l -the third'speed outwards near the case Awall so that the gear runsyery quietly ln'the third speed.

' For. engaging the reverse speed the control rod Itisshifted towardstberightbymeansof mission speed.

the right stop Il, and thus brings the gear wheel w into mesh with the gear wheels u and v. The locking device 22-23-2I .in this instance locks `the control rod and consequently the change clutch member -constructed `as a gear wheel u in its neutral middle position.

As 4shown in the drawing extra space is noty I y required for the reverse speed when the clutch member s is constructed as gear wheel u so that the gear is kept as short and light as possible.

I claim:

1. In a variable speed transmission, a driving shaft, a countershaft.geared thereto, a driven shaft, a plurality of continuously respectively engaging gear wheels on said counter-shaft and driven shaft, a pair of synchronizing clutches respectively rotatable with saidl driven shaft and said 'counter-shaft to provide at least three noiseless forward speeds, one' of said clutches having an annular rim of gear teeth, a fourth shaft. and a gear wheel on said fourth shaft shiftable to interconnect said driven shaft and said counter-shaft through said toothed clutch to provide a reverse drivefor said transmission.

2. The combination according to claim 1, in which the continuously engaging gear wheels are formed with oblique teeth and said clutch and reverse gear with straight teeth.

3. The combination according to claim l, in which the toothed clutch is drivably connected with the driven shaft.

4. In a variable speed transmission, a driving shaft. a counter-shaft geared thereto, a driven shaft, agear wheel and a first synchronizing clutch drivably connected to said driven shaft, a gear wheel rotatably mounted on said driven shaft, said clutch being shiftable between said' driving shaft and said rotatably mounted gear wheel to respectively provide high and low-forward transmission speeds, a gear wheel and a second synchronizing clutch drivablygconnected with'said counter-shaft, said gear wheel being in continuous engagement with the rotatably mounted gear wheel'on said-drivenshaft. a gear wheel rotatablyI mounted on said counter-shaft in continuous engagement with the gear wheel drivably connected with said driven shaft, said 'second synchronizing clutchb/eing shiftable to engage said rotatably mounted gear wheel on said counter-shaft to provide an intermediate forward transmission speed, an annular rim of gear teeth on one of said clutches, a4 fourth shaft, and a gear Wheel on said fourth shaft shiftable t0 interconnect said driven shaft and said countershaft .through said toothed clutch to provide a reverse drive for said transmission.

5. The combination according to claim 4, in

which the first clutch is the toothed clutch.

6. The combination according to claim 4, in which said driven shaft is providedwithanother gear wheel drivably connected thereto and said counter-shaft with another gear" wheel continuously engaging said last gear wheeland rotatably mounted on the other side of said second clutch, said second clutch being also shiftable to engage the other rotatably mounted gear wheel to provide another intermediate forward trans- Tmsonoa xtimnoH. 

